Except for old males, which are solitary, wild boars live in groups.
Sperm whales tend to live in groups of females with their young, while adult males roam further afield singly.
Humans, with the biggest brain/body ratio of all, tend to live in groups of about 150.
The females and young live in groups, while the males remain apart except in the breeding season.
Language, according to the anthropologist Robin Dunbar, evolved because gossip is a more efficient version of the "social grooming" essential for animals to live in groups.
The monkeys typically live in groups of 30 or so, a majority of them genetically related females and their dependent offspring.
The fire took place in one of the campus area's many communal housing units, where students live in groups as large as 15.
Indeed, millions of years ago, fear of predators would have been one of the forces that caused our ancestors to evolve to live in groups.
Chimpanzees also live in groups of a few dozen individuals, and A. afarensis may have stuck with this system.
Adult female and young dolphins normally live in groups of up to 15 animals.
Muskrats normally live in groups consisting of a male and female pair and their young.
